International Laboratory for Brain, Music, and Sound Research (BRAMS), Department of Psychology, University of Montreal, Canada.
Clin Neurophysiol. 2013 Dec;124(12):2378-88. doi: 10.1016/j.clinph.2013.05.013. Epub 2013 Jun 14.
To examine the mechanisms responsible for the reduction of the mismatch negativity (MMN) ERP component observed in response to pitch changes when the soundtrack of a movie is presented while recording the MMN.
In three experiments we measured the MMN to tones that differed in pitch from a repeated standard tone presented with a silent subtitled movie, with the soundtrack played forward or backward, or with soundtracks set at different intensity levels.
MMN amplitude was reduced when the soundtrack was presented either forward or backward compared to the silent subtitled movie. With the soundtrack, MMN amplitude increased proportionally to the increments in the sound-to-noise intensity ratio.
MMN was reduced in amplitude but had normal morphology with a concurrent soundtrack, most likely because of basic acoustical interference from the soundtrack with MMN-critical tones rather than from attentional effects.
A normal MMN can be recorded with a concurrent movie soundtrack, but signal amplitudes need to be set with caution to ensure a sufficiently high sound-to-noise ratio between MMN stimuli and the soundtrack.
探讨在记录 MMN 时，当电影的音轨在呈现时，对音调变化的不匹配负波（MMN）ERP 成分的减少负责的机制。
在三个实验中，我们测量了对音调差异的 MMN，与无声字幕电影中重复的标准音调不同，音轨向前或向后播放，或者音轨设置在不同的强度水平。
与无声字幕电影相比，音轨向前或向后播放时，MMN 幅度降低。随着音轨的出现，MMN 幅度与声音与噪声的强度比的增量成正比增加。
与同时播放的音轨相比，MMN 的幅度降低，但形态正常，很可能是因为音轨与 MMN 关键音之间的基本声学干扰，而不是注意力的影响。
可以在同时播放的电影音轨上记录正常的 MMN，但需要谨慎设置信号幅度，以确保 MMN 刺激与音轨之间有足够高的信噪比。
